Fix the FormSum!?

[Ig-dolci]

Description

No.

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake complex	8125 ran	6527 passed	1585 skipped	13 failed

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake real	8131 ran	7331 passed	786 skipped	14 failed

[JHopeCollins]

Oh dear, if this fixes the issue then that interface could do with updating!

I think that the traversal method is taking advantage of the behaviour described here: #3348 (comment)

This behaviour is not widely known and is quite unintuitive - it's usually considered a bug. It might be best to change this method signature (and the preorder traversal method) to use visited=None as the kwarg, and use a self._visited dict with visited = visited if visited else self._visited

[Ig-dolci]

Oh dear, if this fixes the issue then that interface could do with updating!

I think that the traversal method is taking advantage of the behaviour described here: #3348 (comment)

This behaviour is not widely known and is quite unintuitive - it's usually considered a bug. It might be best to change this method signature (and the preorder traversal method) to use visited=None as the kwarg, and use a self._visited dict with visited = visited if visited else self._visited

No. This does not fix it. I am still debugging.

[JHopeCollins]

No. This does not fix it. I am still debugging.

Shame it wasn't so simple! It may still be good to change the signatures to avoid that behaviour though

[Ig-dolci]

Oh dear, if this fixes the issue then that interface could do with updating!

I think that the traversal method is taking advantage of the behaviour described here: #3348 (comment)

This behaviour is not widely known and is quite unintuitive - it's usually considered a bug. It might be best to change this method signature (and the preorder traversal method) to use visited=None as the kwarg, and use a self._visited dict with visited = visited if visited else self._visited

I see. I gonna try visited=None.

[JHopeCollins]

To have the same caching behaviour as before, without the {} default kwarg, this should stash visited as an attribute so it get's reused unless the user passes visited, e.g.

visited = visited if visited is not None else self._visited